Re: [Qemu-ppc] [OpenBIOS] Apple's BootX

[Jd Lyons]

> On Jan 30, 2018, at 9:10 AM, BALATON Zoltan <address@hidden> wrote:
> 
> On Mon, 29 Jan 2018, Jd Lyons via OpenBIOS wrote:
>> Ok, with a little help for Paul at the kvm-ppc mailing list, it seems the 
>> issue maybe that the BootX or more likely mach_kernel it trying to write 
>> something to or probe for an L3 cache.
> 
> With kvm could be but on TCG it doesn't seem that way. Enabling some SPR 
> debug options in target/ppc/translate_init.c I see this (with qemu git HEAD 
> without other patches):
> 
> $ ppc-softmmu/qemu-system-ppc -cpu G4 -d int
> Write SPR 272 110 <= 07e00000
> Read SPR 287 11f => 000c0209
> Read SPR 25 019 => 07e00000
> Read SPR 25 019 => 07e00000
> Read SPR 287 11f => 000c0209
> Raise exception at fff08978 => 00000003 (40000000)
> Write SPR 273 111 <= 07df7ff0
> Write SPR 274 112 <= 20000004
> Read SPR 272 110 => 07e00000
> Read SPR 273 111 => 07df7ff0
> Read SPR 274 112 => 20000004
> Read SPR 26 01a => fff08978
> Read SPR 27 01b => 40000030
> 
> $ ppc-softmmu/qemu-system-ppc -cpu 7447a -d int
> Write SPR 272 110 <= 07e00000
> Read SPR 287 11f => 80030102
> Read SPR 25 019 => 07e00000
> Read SPR 25 019 => 07e00000
> Read SPR 287 11f => 80030102
> Raise exception at fff08978 => 0000004e (00)
> 
> So OpenBIOS gets unexpected exception very early right after reading the PVR 
> so maybe it's a problem in OpenBIOS before it gets to what you're describing. 
> Is this already fixed?
> 

I’m not sure the question you’re asking, sorry, a lot of this stuff is over my 
head, but I’m trying to understand it.

A lot of the CPU’s in Qemu seem to link back to the 7445 and 7455, and it just 
doesn’t seem to me that emulation is complete for these cpu’s. Changing 
7445/7455 to 7400/7410/604/750 as I said earlier seems to work on some level. 
It will at least get TCG working. Linking the 7447a to 7400/7410 allows this 
CPU to boot the Mac OS, but sadly not with KVM. KVM still raise the L3 cache 
exception. Oddly using the 7448 linked to 7400, as is done in the master now, 
with KVM doesn’t raise this exception, with the mach_kernel that has had the 
CPU “check” removed. 10.4.11 boots happily away.

I’m just not sure what to make of it. 

> Regards,
> BALATON Zoltan
> 
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